If a unit has a dedicated transport, in this case a Chimera, it is not allowed to deep strike or infilrate. Also the unit and Chimera has to start off the table in missions that use the escalation rule.
The troops still use the rules for "infantry" models but are subject to the above rules.

yes they are infantry, but becoz they have a dedicated transport they must start off table in escalation games.

only exception to that rule is something like Tau pathfinders who have the scout special rule. this means they must be deployed and the transport goes into reserve. weird I know, but never the less, correct.